Metabolic Profile of Individuals with and without Type 2 Diabetes from Sub-Saharan Africa.

Epidemiological data predicts that sub-Saharan Africa will have the largest increase in type 2 diabetes (T2D) prevalence over the next two decades. Metabolomics studies have identified biomarkers that could improve T2D diagnosis and follow-up. However, no studies have characterized the metabolome of people from sub-Saharan Africa. Plasma samples from Senegalese individuals with T2D (n = 31) or without T2D (n = 34) were compared using measures of oxidative stress damage and plasma antioxidant enzyme activity and mass-spectrometry-based metabolomics analyses. Results showed that glucose, lactate, and tricarboxylic acid metabolites (fumarate, malate, and succinate) were increased in the T2D group, suggesting alterations in glycolysis and mitochondrial dysfunction. Several amino acids (leucine, isoleucine, valine, and tryptophan) and long-to-very-long-chain fatty acids were higher in the T2D group. Finally, elevated levels of ketone bodies and acylcarnitines were observed along with increased levels of oxidative stress damage and antioxidant activity. In conclusion, the T2D group exhibited modifications in metabolites previously shown to be associated with T2D risk in populations from other areas of the world. Future studies should seek to test whether these metabolites could be used as predictors for T2D-related complications in people from sub-Saharan Africa.

Evaluation of agreement between hemoglobin A1c, fasting glucose, and fructosamine in Senegalese individuals with and without sickle-cell trait.

Fasting glucose (FG) and glycated hemoglobin A1c (HbA1c) perform sub-optimally in people of African origin, especially in individuals with sickle-cell trait (SCT). The purpose of this study was to compare the relationships between HbA1c, FG, and fructosamine in individuals from Senegal with and without SCT. HbA1c, FG, and fructosamine were measured in 203 adults from Senegal (100 control: 45 with type 2 diabetes (T2D); 103 SCT: 51 with T2D). Significant, positive correlations were observed between HbA1c and FG, fructosamine and FG, and fructosamine and HbA1c in both groups. The limits of agreement were inappropriately large in both groups for the Bland-Altman plots of HbA1c and FG (control: -95.97 to 83.97%; SCT: -115.9 to 91.52%), fructosamine and FG (control: -100.6 to 99.89%; SCT: -105.6 to 100.6%), and fructosamine and HbA1c (control: -52.03 to 38.98%; SCT: -88.04 to 71.41%). In both groups, the greatest proportion of subjects were considered above the clinical cut-point for hyperglycemia when fructosamine was used as the criterion (control: 33%; SCT: 44.6%), and the lowest percentage of subjects were classified as over the clinical cut-point when HbA1c was used as the criterion (control: 21%; SCT: 27.7%).Substantial disparities between HbA1c, FG, and fructosamine were observed in both groups, and these differences were exaggerated in the SCT group. Therefore, these three biomarkers should not be considered to be interchangeable measures of glycemic control. These biomarkers should be used thoughtfully, and special care should be taken when using them in individuals with SCT.

Increased Prevalence of Type 2 Diabetes-Related Complications in Combined Type 2 Diabetes and Sickle Cell Trait.

OBJECTIVE: The prevalence of type 2 diabetes (T2D) is rapidly increasing in sub-Saharan Africa, where sickle cell trait (SCT) is also frequent. Although SCT is generally considered a benign condition, evidence suggests that SCT could exaggerate vascular dysfunction in T2D. However, it remains unclear whether SCT could increase the risk of the development of T2D complications. Therefore, this study was conducted to determine whether T2D complications were more prevalent among Senegalese individuals with SCT and T2D than among those with T2D only. RESEARCH DESIGN AND METHODS: Rates of hypertension, retinopathy, peripheral neuropathy, peripheral artery disease, and impaired renal function as well as arterial stiffness, blood rheology, and concentrations of plasma advanced glycation end products (AGEs) and cytokines were compared between groups of Senegalese individuals with combined SCT and T2D (T2D-SCT) (n = 60), T2D (n = 52), SCT (n = 53), and neither T2D nor SCT (control) (n = 56). Human aortic endothelial cell (HAEC) expression of inflammatory and adhesion factors was measured after treatment with tumor necrosis factor-α and subjects' plasma. Effects of AGE inhibition or tiron on HAEC expression of E-selectin were measured. RESULTS: Retinopathy, hypertension, and reduced renal function were more prevalent, and arterial stiffness, blood viscosity at high shear rates, and thixotropic index were higher, in the SCT group compared with the other groups. Multivariable analysis showed that plasma AGE concentration was significantly associated with arterial stiffness. E-selectin expression was elevated in HAECs treated with T2D-SCT plasma compared with the other groups, but AGE inhibition reversed this. CONCLUSIONS: SCT could potentially augment the risk of the development of T2D-related complications, including retinopathy, nephropathy, and hypertension.